Effects Of Exercise On Free Iron Metabolism In Rat Macrophages And Its Mechanisms

Objective:Many studies had indicated that exercise could affect the metabolism of the iron, and it also could affect the ability of exercise by inducing the low iron status. A study had showed a significant decrease in the storage iron and a significant increase of the free iron in the liver and the spleen after exercise. These conclusions may indicate that the metabolism of the iron in the macrophage could be changed by exercise. This study was to observe the effects of exercise on the free iron metabolism in the rat macrophages and its mechanisms.Methods:The adult Spraque-Dawley rats were randomly divided into the sedentary group and the exercise group. The rats in the exercise group swam for 3 months. The rats in the sedentary group remained sedentary throughout the experiment and received approximately the same amount of handling as the exercised rats. At the end of the experimental period, the hematological indices of the iron status by using the biochemical methods were analyzed, the dynamic parameters of the intake of the free iron and the release of the free iron in the peritoneal macrophages by using radioactive ⁵⁹ Fe were analyzed, and both the expression of DMTl and FPNl mRNA in the peritoneal macrophage and the expression of hepcidin mRNA in the liver by using the real-time quantitative PCR were observed.Results:As compared with the sedentary group, in the exercise group the plasma iron and the transferrin saturation had the significant decrease ( P < 0．05 ), but the hemoglobin, the hematocrit and the total iron-binding capacity had no significant changes; the peritoneal macrophages in the exercise group had the significant decrease (P < 0．05 ) both in the free iron uptake and in the free iron release, with had the significant increase( P < 0．01) in the ratio of the free iron release/uptake; the peritoneal macrophages in the exercise group had the significant decrease both in the expression of the DMTl mRNA ( P < 0．01 ) and in the expression of the FPNl mRNA (P < 0．05 ); the liver in the exercise group had the significant increase ( P < 0．01) in the expression of the hepcidin mRNA.Conclusions:The long-term exercise could cause the exercise-induced low iron status. The long-term exercise could significantly affect the iron transport in the macrphage, and it could reduce both the free iron uptake and the free iron release, and could strikingly reduce the free iron uptake. These effects could protect the macrophages against the toxicity of the free iron. The long-term exercise could reduce the expression of the DMTl and FPNl mRNA in the macrophage, and it could increase the expression of the hepcidin mRNA in the liver. As the regulator of iron metabolism, hepcidin could down-regulate the expression of the DMTl and FPNl mRNA to affect the free iron transport in the macrophages. Accompanying these changes of regulating mechanism, the exercise-induced low iron status could be due to the consequence of the regulation in the body. It suggests that the athlete should be cautious of supplementing the iron.